This is certainly a plug, but I’d recommend Learning React from O’Reilly. It’s on Safari now, available for pre-release, and will be out officially in May. It assumes no prior knowledge of React and there’s a related repo with tons of hands-on samples.

I wouldn’t recommend learning React through books. It’s a very small framework, most books i’ve read tried to fill the pages with irrelevant information that does nothing but interrupt your learning process. Try react’s documentation and some small projects.
You can easily find pomodoro clocks in react, then use the documentation to learn how they work. React is very dependant upon implementation, so learning through a book isn’t really an effective method, you must get used to the syntax and understand the purpose of the framework.

I will also agree with books not being that great for React, even if you prefer written stuff for learning. It probably doesn’t need more than one or two chapters of a book. It’s pretty small and there isn’t actually that much new syntax, so the smaller write ups online are good to cover all that without being too overwhelming. Once you are a little familiar with that the hard part is just learning how to ‘think in React’. That’s best learning by doing. Start small and go from there.

To learn the syntax, if you like FreeCodeCamp’s style there is now an alpha version of the React tutorials for FreeCodeCamp available at http://hysterical-amusement.surge.sh/ (Sadly not in the current beta, so not coming any time soon, but the alpha isn’t hard to use, just lacks jumping from one tutorial to another easily.)

I will toot my own horn and suggest my own book: React for Real It’s only about 100 pages, but packs a lot of information. It covers React in a tutorial style, but there’s also a chapter about setting up your own webpack built and even a chapter on Redux basics. I try to give somewhat opinionated advice, so it’s more than just a list of API calls. On the other hand, some people have complained it’s very dense, so it’s probably best if you already have a solid programming experience.

I just finished Robin Wieruch’s, “Road to React,” and thought it was excellent. The book by itself is free, but you can pay for additional resources, if you want. He covers a lot of material and walks you through building a simple program using the Hackernews API. One of the things I liked the most was that he would include additional materials at the end of each chapter/section to learn more. To put things in perspective, I didn’t know anything about React so YMMV if you are more experienced.